KABUL - One is a smooth-talking opposition leader seeking to avenge defeat, the other is a former World Bank economist with a famous temper.
Whoever wins Afghanistan's election will bring a sharp change of style when President Hamid Karzai steps down after 13 years in power and US-led troops end their war against Taliban insurgents.
Abdullah Abdullah and Ashraf Ghani are set to compete in a head-to-head election next month after preliminary results from the first-round vote showed they were the leading two among eight candidates.
Both men are pro-Western, religiously moderate politicians who have played key roles in shaping the country since the fall of the Taliban in 2001.
But they offer voters very different personalities, backgrounds and ethnic loyalties.
Abdullah, 53, is still embittered by the massive vote-rigging that he believes stopped him becoming president in the 2009 election when Karzai retained office, securing a maximum second term.
In 2009, Abdullah came second in the first-round vote and then pulled out of the run-off in disgust, alleging that Karzai's supporters would again try to use fraud to fix the result.
"Abdullah is very professional operator," one diplomat in Kabul told AFP.
"But one concern is how would he work with Karzai, who plans to stay active at the highest levels of Afghan politics."
Abdullah, who started off as an eye doctor, was a member of Burhanuddin Rabbani's government during the 1992-1996 civil war, and made a name for himself abroad for his fluent English and courtly manner.
But his formative political years were as the right-hand man to Ahmad Shah Massoud, the charismatic Tajik commander who led resistance to the 1996-2001 Taliban regime.
Due to his closeness to Massoud, much of Abdullah's core support comes from Tajik and other Dari-speaking ethnic groups in the north.
Massoud was killed two days before the 9/11 attacks on the United States, leaving Abdullah fearing that the anti-Taliban resistance would collapse.